title: Echocardiographical determinants of an abnormal spatial QRS-T angle in chronic dialysis patients.
abstract: BACKGROUND
  The spatial QRS-T angle describes the relation between ventricular depolarization and repolarization. Having a wide (abnormal) angle is considered an important predictor of arrhythmic events. Given the high incidence of sudden cardiac death in dialysis patients, this parameter is of particular interest in this patient group. The objective of this study was to assess the association of (modifiable) echocardiographic parameters and an abnormal spatial QRS-T angle in dialysis patients.
  
  
  METHODS
  A total of 94 consecutive dialysis patients were included. In all patients a 12-lead electrocardiogram (ECG), a two-dimensional echocardiogram and routine blood samples were obtained. The spatial QRS-T angle was then calculated from the 12-lead ECG. An abnormal spatial QRS-T angle was defined as ≥130° in males and ≥116° in females.
  
  
  RESULTS
  An abnormal spatial QRS-T angle was present in 27 (29%) patients. Patients with an abnormal spatial angle had a lower left ventricular ejection fraction (LVEF) of 47 ± 7 versus 55 ± 6% (P < 0.001) and had a higher left ventricular (LV) dyssynchrony, with a septal to lateral (S-L) delay of peak systolic velocity of 70 inter quartile range (iIQR) (40, 100) ms versus 30 IQR (10, 70) ms (P = 0.001), respectively. Multivariate logistic regression analysis controlling for possible confounders demonstrated that LVEF [odds ratio (OR) 0.82; 95% confidence interval (CI) 0.72-0.93, P = 0.001] and LV dyssynchrony (OR 1.19 per 10 ms; 95% CI 1.03-1.38, P = 0.02) were independent determinants of an abnormal spatial QRS-T angle in this patient group.
  
  
  CONCLUSIONS
  LVEF and dyssynchrony are echocardiographic determinants of an abnormal spatial QRS-T angle in dialysis patients and might therefore represent a potential target for the prevention of sudden cardiac death in these patients.
authors.affiliation: Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Mihály K
authors.initials: MK
authors.lastname: de Bie
authors.forename: Nina
authors.initials: N
authors.lastname: Ajmone Marsan
authors.forename: Andre
authors.initials: A
authors.lastname: Gaasbeek
authors.forename: Jeroen J
authors.initials: JJ
authors.lastname: Bax
authors.forename: Victoria
authors.initials: V
authors.lastname: Delgado
authors.forename: Ton J
authors.initials: TJ
authors.lastname: Rabelink
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Schalij
authors.forename: Johan W
authors.initials: JW
authors.lastname: Jukema
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002908:Chronic Disease; D016757:Death, Sudden, Cardiac / Q000453:epidemiology* / Q000473:pathology; D004452:Echocardiography / Q000379:methods*; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D006435:Renal Dialysis; D016277:Ventricular Function, Left
keywords: dialysis; left ventricular dyssynchrony; spatial QRS-T angle; sudden cardiac death